Place the raspberries in a medium-sized saucepan, sprinkle with the sugar, squeeze over the lemon juice and pour over the water.

Over a medium heat bring the mixture to a boil. Stir a few times to dissolve the sugar. Turn down and simmer for about 6-7 minutes or until the raspberries disintegrate.

Remove from the heat and allow to cool slightly. Pass through a fine meshed sieve to strain, pressing down on the fruit. Most of the raspberry flesh should be soft enough to pass through, leaving the pips behind.

Allow to cool, then pour into a glass vessel and place in the fridge.

To serve the spritzer, pour a some of the cordial in a glass and top off with seltzer or to make it extravagant some bubbly Prosecco.